A wireless optical communications technology is also called visible light communication, where communication is performed by flashing an LED light source at a high frequency, presence of light indicates 1, and absence of light indicate 0, and a transmission rate can reach a maximum of gigabits per second. In the wireless optical communications technology, data is unlikely to be interfered or captured, and an optical communication device can be easily made and are unlikely to be damaged or demagnetized. Therefore, the wireless optical communications technology can be used to make a wireless optical encryption key. Compared with a microwave technology, wireless optical communication has relatively rich spectrum resources, which is unmatched by common microwave communication and wireless communication; in addition, visible light communication can be applicable to any communications protocol, and is suitable for any environment; in terms of security, compared with conventional magnetic materials, there is no need to worry about a problem of degaussing, or even to worry about that communication content is intercepted; and optical wireless communication equipment features flexible and convenient installation and layout, and low costs, and is applicable to large-scale popularity and application.
The Internet of Things is a network that is based on an information carrier such as the Internet, a conventional telecommunications network, or the like, so that all common physical objects that can be individually addressable can implement interconnection and interworking. The Internet of Things refers to that ubiquitous terminal devices and facilities implements interconnection and interworking by using various wireless or wired long-distance or short-distance communications networks to provide secure, controllable and even personalized management and service functions such as real-time online monitoring, positioning tracing, alarm linkage, scheduling and dispatching, plan management, remote control, security protection, remote maintenance, online upgrade, statistical reporting, decision-making support, and leader desktop, so as to implement integration of “management, control, and operation” of high efficiency, energy saving, security, environmental protection of devices. A conventional Internet of Things generally implements interconnection and interworking by using various wireless or wired communications networks, and uses a conventional communications technology.
In the prior art, there is an Internet of Things technology that implements short-distance communication by means of transmission of visible light in free space, and the Internet of Things using the visible light communications technology is called the photonic Internet of Things. The photonic Internet of Things has functions of a conventional Internet of Things, and performs communication by using visible light in terms of communication mode. Because visible light has high directivity, and cannot penetrate a barrier, and therefore has higher security than wireless transmission, the photonic Internet of Things that uses visible light to implement short-range communication has higher security than an Internet of Things that uses a wireless communication mode.
However, in the current photonic Internet of Things technology, original data is not encrypted, but a signal is modulated directly onto a visible light signal for transmission, or a data source is only simply encrypted, for example, a logical operation is performed on the original data and a scrambling code, while a scrambling code sequence remains unchanged. In this case, there might be a security risk, for example, when a high-speed camera is used for shooting, a light signal with a same strobe might be replicated, and then when an LED transmitter of the same type is used to transmit such type of signal, a receive control end may recognize the replicated signal and consider the replicated signal legal, and can correctly restore the original signal, so as to control a device, for example, enabling an access control system, thereby leading to a security risk.